1. Field of the Invention (Technical Field)
The present invention relates to an antenna and exciter systems for vehicles, such as automobiles, trucks, trains, buses, boats and aircraft.
2. Description of Related Art
Note that the following discussion refers to a number of publications by author(s) and year of publication, and that due to recent publication dates certain publications are not to be considered as prior art vis-a-vis the present invention. Discussion of such publications herein is given for more complete background and is not to be construed as an admission that such publications are prior art for patentability determination purposes.
The automobile manufacturing industry is undergoing an industry wide revolution to provide connectivity to automobiles. This field of endeavor has been coined as “telematics” by the automotive industry. Connectivity is required for AM/FM radio, cellular, GPS, internet and satellite linkage. The first phase of this revolution has already begun. All high-end model automobiles, such as those produced by Chrysler, Daimler-Benz and Cadillac, have already eliminated external antennas on the top side of their vehicles. These antennas have been moved to the front and rear windows of the automobile. Many automobiles will be so equipped in the next several years.
Now that automobile connectivity is often used for emergency services, the survival of the antennas becomes a paramount issue. Unfortunately, one of the first things to be destroyed is the windows along with their antennas. In a severe accident, the automobile may often be upside down with the under-chassis pointed skyward. The telematics systems must be able to function even in this case.
The problem of providing a solution for a survivable antenna connectivity for vehicles has presented a major challenge to engineers and technicians in the automotive industry. The development of methods and apparatus that would supply a survivable antenna for vehicles would constitute a major technological advance, and would satisfy a long felt need within the automobile industry.
Several patents disclose an under-vehicle antenna. These include U.S. Pat. No. 2,111,398, entitled “Antenna Device” to Kippenberg; U.S. Pat. No. 2,073,336, entitled “Radio Ground Exciter” to Cook; and U.S. Pat. No. 4,968,984, entitled “Antenna Unit for a Vehicle” to Katoh, et al. None of these patents disclose the use of a discone-type of exciter.
Prior art discones do not have a coaxial cable extending through the cone portion. U.S. patent application Ser. No. 10/160,747, entitled “Exciter System and Excitation Methods for Communications Within and Very Near to Vehicles,” and U.S. patent application Ser. No. 635,402, entitled “In-Vehicle Exciter”, which are incorporated herein by reference, disclose a modified discone exciter, which is used for communications within a vehicle. The present invention is directed to a modified discone exciter, with a coaxial cable disposed in the cone, for communications outside the vehicle.